OPENAI VS DEEPSEEK
GPT-5.6 Luna vs DeepSeek V4 Flash
DeepSeek V4 Flash is about 2.6x cheaper than GPT-5.6 Luna on a blended 3:1 input:output rate — the same 10K-in/2K-out request costs $0.002 vs $0.0044. GPT-5.6 Luna has the larger context window (1,047,576 vs 1,000,000 tokens).
Pricing verified
API pricing per 1M tokens
| Model | Input / 1M tokens | Output / 1M tokens | Blended (3:1 mix) |
|---|---|---|---|
| GPT-5.6 Luna | $0.20 | $1.20 | $0.45 |
| DeepSeek V4 Flash | $0.14 | $0.28 | $0.175 |
Rates from official OpenAI pricing and official DeepSeek pricing, checked 2026-08-11.
What a real workload costs
Example: one request with 10,000 input tokens and 2,000 output tokens, then that request at 100,000 runs per month.
| Model | Per request (10K in / 2K out) | Per month (100K requests) | Monthly delta |
|---|---|---|---|
| GPT-5.6 Luna | $0.0044 | $440 | +$244 |
| DeepSeek V4 Flash | $0.002 | $196 | — |
Model your own prompt sizes and volumes in the token cost analyzer, or check caching savings with the prompt caching calculator.
Specs side by side
| Spec | GPT-5.6 Luna | DeepSeek V4 Flash |
|---|---|---|
| Provider | OpenAI | DeepSeek |
| Context window | 1,047,576 tokens | 1,000,000 tokens |
| Model class | General text | General text |
| Tokenizer | o200k_base (exact, public) | Proprietary (counts estimated) |
Count tokens for each model on its own page: GPT-5.6 Luna token counter and DeepSeek V4 Flash token counter. All OpenAI models are on the OpenAI Token Counter. All DeepSeek models are on the DeepSeek Token Counter.
FAQ
GPT-5.6 Luna vs DeepSeek V4 Flash FAQ
Which is cheaper, GPT-5.6 Luna or DeepSeek V4 Flash?
DeepSeek V4 Flash is cheaper. At rates checked 2026-08-11, GPT-5.6 Luna costs $0.20 input / $1.20 output per 1M tokens, while DeepSeek V4 Flash costs $0.14 input / $0.28 output — about a 2.6x difference on a typical 3:1 input-heavy workload.
How much does a real request cost on GPT-5.6 Luna vs DeepSeek V4 Flash?
A request with 10,000 input tokens and 2,000 output tokens costs about $0.0044 on GPT-5.6 Luna and $0.002 on DeepSeek V4 Flash. At 100,000 such requests per month that is $440 vs $196 — a difference of $244 per month.
Which has the bigger context window, GPT-5.6 Luna or DeepSeek V4 Flash?
GPT-5.6 Luna. It supports 1,047,576 tokens of context versus 1,000,000 tokens — roughly 786,000 English words in one request.
Do GPT-5.6 Luna and DeepSeek V4 Flash count tokens the same way?
Not exactly. GPT-5.6 Luna uses the published o200k_base tokenizer and DeepSeek V4 Flash uses a proprietary tokenizer (counts are estimates). The same prompt will tokenize differently, which shifts effective cost per word.